Improvement in round beltings



' A.HoLBRooK,1r

Round Belting.

' Patented June18, 1872.

IUNITED STATES ALBERT HOLBROOK, JR., OF PROVIDENCE, RHODE ISLAND,ASSIGNOR TO A. & C. W. HOLBROOK, OF SAME PLAGE.

IMPROVEMENT IN ROUND BELTINGS.

Specification forming part of Letters Patent No. 128,040, dated June 18,1872. l

Specification describingia new and useful Improvement in Round Belt-ing,invented by ALBERT HoLBRooK, Jr., of Providence, in the county ofProvidence and State of Rhode Island.

My invention consists in folding the margins of the strap which is to betwisted into a spiral round belt over upon the inner portion beforetwisting it, adjusting the said parts folded so as not to extend quiteto the center, or so as to meet when lying fiat, by which I have roundededges meeting together along the spiral line where the edges .meettogether, which gives a much better and neater finish than the raw edgesof the ordinary arrangement. They are also stronger, and do not swell orbend outward, as the raw edges do by the action of the great pressureagainst each other to which they are subject by the bending of the beltaround the pulleys, and the edges lapped over on the middle portion formthe core, around which the said middle portion becomes twisted, and thussaves the sewing on of another strip for forming a core, as in thecommon way of making round belting. A belt formed in this way bends moreuniformly than the others, which tend to bend short at the crossing ofthe exterior of the curve by the line between the edges of the spirals,which allows the spirals to so separate or open that all the tensioncomes upon the inside'.

Figure 1 is a side view of a section of round Abelting made according tomy improvements, a part being untwisted toshow the construction of thestrap before being twisted up. Fig. 2 is a cross-section of Fig. l onthe line x, and Fig. 3 is a cross-section on the line y y.

Similar letters of reference indicate corresponding parts.

A represents the margins folded over on the middle portion of the strap,as aforesaid. These parts are so adjusted with reference to the distanceof the edges from the center that they will come together and form acore, as represented in Fig. 3, around which the main portion wraps andconfines it compactly. But in this respect the arrangement of the saidfolded part-s will be modified, as circumstances may require, or as theconditions vary-for instance, the thickness of thestrap of leather, thebreadth of the part B, and the pitch ot' the spiral coils. v

If the leather is thin and a belt of greater diameter be required'thancould be made when folded, as in Figs. 1 and 2, the margins A might beso wide as to lap each other and thus form a double core when twistedup.

Having thus described my invention, 1 claim as new and desire to secureby Letters Patent- A round twisted belt, formed of a strap, B, with themargins A folded over on it before being twisted, substantially in themanner specified.

ALBERT HOLBROOK, JR.

Witnesses:

CHARLES SELDEN, JOHN G. PURKIs.

PATENT OFFICE.

